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Symposia
What Makes an Ecological Icon?
A symposium organized by Aaron Ellison (Har‑
vard Forest) and Paul Dayton (Scripps), at the
91st ESA Annual Meeting at Memphis, Tennes‑
see, August 2006.
Progress in science occurs as new theories are
developed and subsequently revised in light of em‑
pirical data that challenge hypotheses derived from
the theories. Scientific theories and hypotheses are
developed, and data are collected, by individuals
(and collaborative groups); their ideas and results
are disseminated to the broader community in pub‑
lications, both technical and non-technical. Some of
these individuals become icons; their work is well
known and they achieve recognition for their sub‑
stantive contributions through extensive citation of
their published work. Others are cited rarely, if ever,
and they fade into obscurity. At a time when the
availability of academic jobs continues to decline,
while the number of new Ph.Ds in ecology contin‑
ues to increase and the Annual Meetings of the Eco‑
logical Society of America (ESA) take on the aura
of a job fair cum meat market, it seemed timely to
ask why some ecologists achieve iconic status for
their work, but others are quickly forgotten, even
if the latter published the same ideas or data before
the former. Further, losing the historical context for
our work, and the disappearance from contemporary
literature of carefully garnered data and results, can
lead to unnecessary repetition of research, slowing
progress in the field and wasting scarce resources.
In the symposium, “What makes an ecological
icon?” a group of seven ecologists and historians
discussed individuals—some well known, some
forgotten—who made substantive contributions to
the development of fundamental ideas in ecology,
including the following: the concept of food webs;
invasive species and community assembly; the eco‑
system concept; nonequilibrium dynamics; and the
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Bulletin of the Ecological Society of America
Fig. 1. Charles Elton (1926). Photo used with
permission.
value of conservation and preservation. Both during
their formal presentations and in the lengthy discus‑
sion following the symposium, the speakers also ad‑
dressed how current norms of scholarship and publica‑
tion, and mechanics of web-based literature searches
and journal-imposed rules for citations inadvertently
encourage contemporary researchers to ignore histori‑
cal antecedents and duplicate past work.
Food webs and invasive species are central top‑
ics around which much of contemporary community
ecology revolves. Models of how complex networks
are structured have reinvigorated theoretical inves‑
tigations of food web structure (e.g., Pascual and
Dunne 2006), and the increasing rates of spread of
nonindigenous species provide unfortunate opportuni‑
ties to empirically test these models as food webs are
restructured following novel introductions. If asked,
most ecologists would trace the origin of food web
theory and studies of invasive species to Charles Elton
(Fig. 1). His “food cycle” of Bear Island (Summer‑
hays and Elton 1923: Fig. 2) was reprinted in his 1927
text Animal Ecology. It was subsequently
reproduced widely and is often held up as
the first food web, although it is pre-dated
by similarly illustrative diagrams pub‑
lished by Pierce et al. (1912) and Shelford
(1913), among others. Elton’s other influ‑
ential book, The Ecology of Invasions by
Animals and Plants (Elton 1958) is gener‑
ally considered to ground most contempo‑
rary research into the causes of success‑
ful species introductions and the impacts
of invasive species. But both food web
ecology and invasion biology have deeper
roots.
Frank Egerton (Fig. 3 ), a historian of
science whose articles on the History of Ecology have
been appearing in nearly every issue of the ESA Bulletin since 2001, traced the development of the food web
concept back to the early 18th century and the writing
of naturalist Richard Bradley (1718, Part 3:60-61)
Fig. 2. Elton’s “food cycle”. From S.V. Summer‑
hays and C.S. Elton (1923).
… Insects which prey upon others are not with‑
out some others of lesser Rank to feed upon them
likewise, and so to Infinity; [that] there are Beings
subsisting which are not commonly visible may be
easily demonstrated…in a Microscope.
This concept was popularized by Jonathan Swift
(1733: lines 341-344):
So, Nat’ralists observe, a Flea
Hath smaller Fleas that on him prey,
And these have smaller yet to bite ‘em,
And so proceed ad infinitum.
Jonathan Fisher, a fifth-year graduate student at the
University of Pennsylvania, illustrated more quantita‑
tive antecedents to food web research, including an ex‑
tended discussion of the work of Harold Colton (Fig.
4 ), a student at Penn in the early 20th century, and a
faculty member there until 1926. Colton was a found‑
ing member of the ESA (ESA 1972) and authored a
paper on competition and predation in the rocky inter‑
tidal (Colton 1916) that covers much the same ground
Fig. 3. Frank Egerton. Photo by Liana J. Cooper
(c) The Journal Times (Racine, WI), and used with
permission.
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October 2006 381
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Although Elton’s book is generally considered a foun‑
dational text, Carlton illustrated that it was really a
selective set of case studies (neither Guthrie-Smith’s,
Clark’s, nor Lindroth’s work was even cited by El‑
ton). It was well received because unlike the others, it
was short, well-written, and appeared at a time when
concern about environmental change was taking off.
Elton also popularized his work through radio broad‑
casts, popular writings, and public lectures. While our
results and theories will be more accessible and wide‑
ly read if our papers are written clearly and concisely,
an unfortunate lesson of Carlton’s talk is that selec‑
tive citation and incessant self-promotion can lead to
iconic status, whether or not it is well deserved.
Fig. 4. H. S. Colton (ca. 1916) from the Mu‑
seum of Northern Arizona collection (No. 7422).
Reprinted with permission.
as more well-known icons of the intertidal (e.g.,
Menge and Sutherland 1976; see the comprehensive
review by Fisher 2005). An abstract of Colton’s pa‑
per was published in Science in 1916, and many of his
other papers on intertidal biology were widely cited.
In modern times, he is better remembered for his ar‑
chaeological research in the desert southwest (Miller
1991). His work on intertidal food webs, however, is
generally forgotten
Colton’s work is particularly intriguing because
his food web lacks the European green crab, Carcinus
maenas, which is now an invasive species in Maine
where Colton studied (as well as elsewhere in the
United States); trawling the historical literature could
provide crucial data that can be used to provide base‑
lines from which to assess the impacts of other current
invasions. Jim Carlton, Director of the Williams-Mys‑
tic Maritime Studies Program (Williams College and
Mystic Seaport) discussed how the baseline require‑
ments of successful invasion—including entrainment,
transport, and spread of species during emigration;
discharge, survivorship, reproduction, and establish‑
ment during immigration—the unification of which in
“invasion biology” is attributed to Elton (1958), can
all be found in earlier books, notably those by Guth‑
rie-Smith (1921), Clark (1949), and Lindroth (1957).
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Bulletin of the Ecological Society of America
Important work by notable ecological icons may
also be forgotten. G. Evelyn Hutchinson (Fig. 5 ) is
well known to ecologists; the niche as n-dimensional
hypervolume (Hutchinson 1957) and constant sizeratios among competitors (Hutchinson 1959) laid the
foundation for a vast amount of ecological research in
the 1960s and 1970s that was focused on equilibrium
dynamics (both papers were reprinted in Real and
Brown’s Foundations of Ecology collection [1991]).
Saran Twombly, a program director at NSF and
Hutchinson’s last graduate student, explored in detail
the roots of nonequilibrium theory in Hutchinson’s
work (especially Hutchinson 1953). This work is vir‑
tually unknown to contemporary ecologists, although
tests of Hutchinson’s nonequilibrium theories pervade
the limnological literature (e.g., Reynolds 1980/1984,
Sommer 1985). Hutchinson’s relatively obscure style
of writing (clearly evident in his 1978 textbook), his
uninformative (to search engines) titles (e.g., Hutchin‑
son 1957, 1959), and the tireless promotion by his stu‑
dents of equilibrium theory (e.g., MacArthur and Wil‑
son 1967) together likely led to the disappearance of
Hutchinson’s nonequilibrium ideas from the general
ecological literature.
Another example can be found in the life and work
of Victor Shelford (Fig. 6). Shelford, whose early
work on food webs (1913) was discussed above, was
the Founding President (1916) of the ESA. Less well
known among ecologists is his role 30 years later in
the founding of The Nature Conservancy (TNC), a
role that is now recognized by TNC’s Victor Shelford
Award for Science in Conservation (ironically restrict‑
ed to past or current TNC employees). Sara Tjossem, a
historian of science at Columbia University, reviewed
Shelford’s career and highlighted the origins of the
(still ongoing) tensions within the ESA membership
between “basic” ecological science and environmen‑
tal advocacy. As ESA President, Shelford established
(and chaired) a committee on preservation, to carry
out an ecological resource inventory of the U.S., and
to initiate and carry out action concerned with the
preservation of hundreds of natural areas. Part of his
motivation was to preserve areas in undisturbed con‑
dition as benchmarks for future ecological research.
But by the 1930s, the leadership of the ESA had fo‑
cused the Society’s activities on basic research and re‑
moved both political and financial support from envi‑
ronmental advocacy and land protection. In response,
Shelford founded the Ecologist’s Union (1946), which
was reorganized and renamed in 1950 as The Nature
Conservancy.
One of Shelford’s students was Eugene Odum, who
along with his younger brother Howard (Tom) Odum
(a Hutchinson student) are considered the founders
of ecosystem ecology, the roots of which can also be
traced to Hutchinson’s student Ray Lindeman’s (1942)
paper on food webs! Historian Joel Hagen (Radford
University) delved into the personalities of the Odum
brothers, exploring the cultural and scientific context
and timeline of their most influential work, which was
in many ways a progressive response to the co-inci‑
dent ascendancy of rampant individualism in America
(exemplified by the work of Ayn Rand [1965], Barry
Commoner [1966] and the presidency of Ronald Rea‑
gan) and of reductionism in ecology (e.g., Williams
[1966] and Dawkins [1976]). Hagen has explored the
conceptual roots of ecosystem ecology elsewhere (Ha‑
gen 1992); in his symposium presentation he argued
that the Odum brother’s broader ideas—of emergy,
holism, and social progressivism—have been lost to
ecosystems ecology, which focuses more narrowly
on cycling of nutrients and energy. Hagen further ar‑
gued that the ecosystem concept remains marginalized
within ecology as a whole. Although many ecologists
Fig. 5. G. Evelyn Hutchinson as a student in
1920 collecting the meadow spittlebug, Philaenus
spumarius, Cherryhinton Chalk Rt, Cambridge.
Both this photo and that of Elton (Fig. 1) attest to
the decline in the quality of ecologists’ attire since
the early 20th century! Photograph from the G.
Evelyn Hutchinson Papers, image 6290; Manu‑
scripts and Archives, Yale University Library, used
with permission.
may dispute this point, the relatively low number of
papers on “ecosystem ecology” published in the ESA
journals and the continued split between “population
and community” ecology and “ecosystems” ecology
by federal funding agencies lend credence to Hagen’s
argument.
So why are some individuals remembered while
others are forgotten? Why are some contributions
rapidly catapulted into widely cited paradigms while
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October 2006 383
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stated, “keep publishing or vanish”). But as we have
seen, publishing is clearly not enough; others must
read what we write and cite it. Scholarship demands
that the burden of reading the literature is on each
scientist, but reading is also not enough. We not only
read the literature, but in our choices of citations, we
propagate some ideas and prune others. With a meta‑
phor that would be familiar to most ecologists, David
Hull (1988:376–377) suggested that
If science is a selection process, transmission is
necessary. Disseminators are operative in this
process. Perhaps they do not get the ceremonial
citations that patron saints do, but they are liable to
get much more in the way of substantive citations.
. . . To the extent that disseminators substitute their
own views for the patron saints whom they cite
ceremoniously, they are functioning as germ-line
parasites—the cowbirds of science.
Fig. 6. Victor Shelford (1940).
others remain buried and unread in the pages of our
journals? Should current upstarts aspire to iconic sta‑
tus? In his wide-ranging talk, Paul Dayton explored
these central questions of the symposium by peering
through the lenses of norms of scholarship, the peer
review process, and dynamics of citation. A central
nugget, attributable to Lamarck (1984 [1809]:404), is
that
Men who strive in their works to push back the
limits of human knowledge know well that it is not
enough to discover and prove a useful truth previ‑
ously unknown, but that it is necessary also to be
able to propagate it and get it recognized.
This sentiment is encapsulated in the well-known
maxim, “publish or perish” (which, given the over‑
whelming flood of literature, would be more aptly
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Bulletin of the Ecological Society of America
(This parasitism process is modeled quantitatively
by the economists Myong-Hun Chang and Joseph
Harrington [2006], using analysis of social networks
that are similar to methods being independently devel‑
oped and used by food-web ecologists [see papers in
Pascual and Dunne 2006]. How can we (or should we)
reduce the influence of these cowbirds?
New articles in ecology are being published at an
ever-increasing rate. More and more, we rely on title
and keyword searching of electronic indices and tertia‑
ry reviews (such as those found in Trends in Ecology
and Evolution or Annual Reviews of Ecology, Evolution, and Systematics) to keep abreast of the literature
in our ever-narrowing subdisciplines. Even the most
extensive online databases, such as ISI’s Science Cita‑
tion Index (Web of Science), do not cover all sources
or the temporal span of modern ecology. Many jour‑
nals, including outlets for new findings as well as re‑
view journals, limit the number of citations per article,
discourage citing articles >10—15 years old, and/or
encourage citation of articles published in the journal
to which the paper is submitted (a strategy intended to
increase a journal’s impact factor). All of these trends
should be resisted. Journals that limit the number of
citations per article usually provide options for on-line
appendices, in which more extensive citations can,
and should, be placed and discussed. Writers of re‑
views should make it known to journal editors, and es‑
pecially our students, that ecology’s roots extend back
more than a decade. Impact factors are notoriously
unreliable (Anonymous 2002), and we should neither
concern ourselves with them nor encourage their use
in making decisions about publication outlets, much
less hiring decisions.
As Jonathan Fisher suggested, we should all try to
resurrect unappreciated classics. This can be done by
consciously using data from, and appropriately cit‑
ing, relatively unknown but useful books and papers;
try to cite one such paper in each article you write.
As Fisher illustrated in his review of rocky intertid‑
al ecology in the early 20th century (see also Fisher
2005), many of these may be in foreign languages, the
reading of which poses a problem for students who
no longer have to master a second language as part
of their graduate education. These can be translated
using Google Translate ‹http://translate.google.com›,
and if they are in the public domain (as most works
>50 years old are), posted on the Web. At the same
time, we should (re)read, and encourage our students
to read, well-known classic papers, such as those in
Real and Brown (1991). Ecologists know that current
ecological processes and dynamics are controlled or
constrained by land-use history and past ecological
events (e.g., Foster and Aber 2004). Similarly, con‑
temporary ecological thought is bounded and shaped
by the work of individuals who have come before us.
Ecologists would do well to remember George San‑
tayana’s oft-quoted aphorism, “[t]hose who cannot
remember the past are condemned to repeat it” (San‑
tayana 1905–1906:284). In times of rapid ecological
and environmental change, we do not have the time or
resources to continually repeat the good work that has
already been done.
Acknowledgments
I sincerely thank Paul Dayton, the symposium
co-organizer; and Jim Carlton, Paul Dayton, Frank
Egerton, Jonathan Fisher, Joel Hagen, Sara Tjossem,
and Saran Twombly for their thoughtful contributions
to the symposium. Any misrepresentations of their
work in this essay are my responsibility.
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Aaron M. Ellison, Organizer
Harvard University
Harvard Forest
Petersham, MA 01366 USA